The present invention relates to conveyor systems in general, and more particularly to improvements in conveyors of the type wherein a trolley, a telpher, a cage, a gondola or another suitable vehicle or conveyance is confined to movement along a single rail.
A drawback of presently known monorail conveyors is that many sensitive parts of the conveyance (i.e., of the vehicle which moves along a rail, normally an overhead rail) are exposed and are subjected to the influence of dust or other foreign matter. Furthermore, exposure of certain parts in electrically powered vehicles is dangerous to attendants, e.g., when the monorail system is used in the assembly hall, magazine or another section of a manufacturing or like plant. As a rule, the vehicle is mounted for travel along an I-shaped rail. It is also known to employ U-shaped rails wherein the web is located at the lower ends of the flanges, i.e., the rail is open at its upper side so that all descending foreign matter can accumulate in its interior to interfere with movements of the vehicle if the latter comprises parts which extend upwardly along the outer sides of the flanges and thereupon downwardly into the interior of the rail.
In most instances, the vehicles are driven by electrically powered motors which transmit torque to gears in mesh with stationary toothed racks which are secured to the rails. Such construction of driving means is satisfactory, except that the motor, the gear and/or the rack is likely to be contaminated by dust or other foreign matter to thus interfere with predictable movement of vehicles along the rails.